Finding the Fourth Proportional to 128,669.88, 177,564.30 and 72,081.30

Step by Step Solution

1. Step 1: Write the proportion equation
   128,669.88 : 177,564.30 = 72,081.30 : x
2. Step 2: Convert to fraction form
   128,669.88/177,564.30 = 72,081.30/x
3. Step 3: Cross multiply
   128,669.88x = 177,564.30 × 72,081.30
4. Step 4: Simplify right side
   128,669.88x = 12,799,065,577.59
5. Step 5: Solve for x
   x = 12,799,065,577.59/128,669.88
6. Step 6: Final answer
   x = 99,472.12